Epoxy coating materials are well known and have gained commercial acceptance as protective and decorative coatings for steel, aluminum, galvanizing, wood and concrete in maintenance, marine, construction, architectural, aircraft, automotive, flooring, and product finishing markets. The basic raw materials used to prepare these coatings generally comprise as essential components (a) an epoxy resin, (b) a hardener, and (c) pigment, aggregate, or other components.
The epoxide resins are those having more than one 1,2-epoxy group per molecule and may be saturated or unsaturated, aliphatic, cycloaliphatic, or heterocyclic. The epoxy resins generally contain glycidyl ester or glycidyl ether groups and have a weight per epoxide of 100 to 5,000. The hardener is typically chosen from the general classes of aliphatic amines or aliphatic amine adducts, polyamides, polyamidoamines, cycloaliphatic amines, aromatic amines, Mannich bases, ketimines, and carboxylic derivatives. Pigments and aggregates include, for example, titanium dioxide and other inorganic and organic color pigments, silica, barium sulfate, magnesium silicate, calcium silicate, fumed silica, garnet, feldspar, carbon black and the like.
Epoxy based protective coatings represent one of the most widely used methods of corrosion control. They may be used to provide long term protection of steel, concrete, aluminum, and other structures under a broad range of corrosive conditions, extending from atmospheric exposure to full immersion in strongly corrosive solutions. For over 20 years, these coatings have been formulated from either a solid or liquid epoxy resin cured with an aliphatic polyamine or polyamide resin, e.g., Shell Epon 1001, or Epon 828 epoxy resins cured with diethylene triamine (DETA) or Versamid 100 series polyamides. In typical two package coating systems, the epoxy resin component is usually the vehicle for pigment grinding and dispersion of other aggregates and various additives.
Epoxy based protective coatings posses many properties which make them desirable as coating materials. They are readily available and are easily applied by a variety of methods including spraying, rolling and brushing. They adhere well to steel, concrete and other substrates, have low moisture vapor transmission rates, act as barriers to water, chloride and sulfate ion ingress, provide excellent corrosion protection under a variety of atmospheric exposure conditions and have good resistance to many chemicals and solvents.
Epoxy based materials may also be formulated as surfacers or flooring materials primarily for application over concrete. For example, one commercially successful epoxy based flooring material utilizes liquid bisphenol A epoxy resin and a modified aliphatic polyamine combined with graded silica sand aggregate.
Certain epoxy based coating and flooring materials may not display good resistance to weathering in sunlight. While such coatings may maintain their chemical and corrosion resistance, exposure to the ultraviolet (UV) light component of sunlight may result in a surface degradation phenomenon known as chalking which changes both the color and gloss retention of the original coating. Where color and gloss retention is desired or required, epoxy protective coatings are typically top-coated with a more weatherable coating, such as an alkyd, vinyl or aliphatic polyurethane coating. The end result is a two or sometimes three coat system which provides the desired corrosion resistance and weatherability, but which is also labor intensive and expensive to apply.
In addition, epoxy based coating and flooring materials require resistance to mechanical abuse. For example, coated materials may be subjected to impact or flexing which may result in cracking or other imperfections in the epoxy coating. Subsequent exposure to weathering or chemicals may result in contact with chemicals and the underlying surface materials, potentially resulting in oxidation of the underlying material, degradation of the epoxy coating from the underside, and/or release of the epoxy coating from the surface.
While epoxy based coating and flooring materials have gained wide commercial acceptance, the need nevertheless remains for epoxy based materials with improved chemical and corrosion resistance, resistance to mechanical abuse (such as flexing or impact), and improved color or gloss retention. Epoxy coatings and flooring materials with improved color and gloss retention are needed wherever they may be exposed to sunlight. An epoxy coating which doesn't chalk and does not require a weatherable topcoat is desirable. Coating and flooring materials with improved chemical, corrosion, impact, flex, and abrasion resistance are needed for both primary and secondary chemical containment structures, for protecting steel and concrete in chemical, power generation, railcar, sewage and waste water treatment, automotive, and paper and pulp processing industries Improved epoxy based flooring materials are needed in industrial environments such as shipping and receiving docks where heavy impact loading can be anticipated, for floors which must be repeatedly cleaned with steam and aggressive chemicals, such as those found in food processing, meat packaging and beverage industries and where spills of caustic, acid and highly reactive chemicals cannot be avoided.
Therefore, the present disclosure provides for new epoxy based coating and flooring compositions displaying one or more of improved chemical resistance, resistance to weathering, corrosion resistance, resistance to mechanical abuse, flexibility, high tensile and compressive strength, and excellent resistance impact and abrasion.